A typical X-ray imaging system comprises an X-ray source and an X-ray detector. The X-rays that are emitted from the X-ray source can impinge on the X-ray detector and provide an X-ray image of the object (or objects) that are placed between the X-ray source and the X-ray detector. In one type of X-ray imaging system, a fluoroscopic imaging system, the X-ray detector is often an image intensifier or, more recently, a flat panel digital detector.
In many medical imaging applications, a collimator is placed between the X-ray source and the X-ray detector to limit the size and shape of the field of the X-ray beam. The collimator can shape or limit the X-ray beam to an area of a patient's body that requires imaging, preventing unnecessary X-ray exposure to areas surrounding the body part that is being imaged and protecting the patient from needless X-ray exposure. And because the collimator can limit the X-rays impinging on the X-ray detector near the body part being imaged, the collimator helps improve image contrast and quality. For example, the collimator can reduce excess X-rays from impinging on a flat panel digital detector, reducing or preventing image blooming or bleeding (which tend to occur when the detector is overloaded with X-rays). Thus, some conventional collimators can minimize X-ray exposure and maximize the efficiency of the X-ray dosage to obtain an optimum amount of data for diagnosis.